The present invention relates to an airship, and more particularly, to a system for tilting polarization and steering main beam of airship antenna and ground station antenna using GPS (Global Positioning System), which can maintain reliable telecommunication link by aligning polarization and main beam of airship antenna and ground station antenna each other from azimuth and elevation coordinates of airship.
Generally, an high altitude unmanned airship makes a long stay at an altitude of 10-20 Km to perform various functions of satellite such as telecommunication relay, remote exploration, weather forecast, scouting and monitoring and the like.
This airship can float by itself by buoyancy difference from air, so that it flies through the stratosphere, stable air layer, and performs these functions.
FIG. 1 represents the configuration of general airship ground station system. Wherein, airship and ground station system means airship 100 and ground station 150, which communicates with the airship 100, and it is applied over the whole specification.
As shown in FIG. 1, the 1st GPS receiver 120 having GPS antenna 121 is located in the airship 100.
The airship 100 includes shelter 102, which is equipped with telecommunication device, engine, equipment and the like, in the bottom part of it.
The shelter 102 includes airship antenna, which is the antenna for communicating with ground station 150 and is called xe2x80x9cairship communication antennaxe2x80x9d sometimes.
And, the ground station 150 makes wireless communication with the airship 100 and receives information from the airship 100. The ground station 150 is divided into stationery station and moving station.
The ground station 150 includes ground station antenna 160 for communicating with the airship 100 and the 2nd GPS receiver 170 for receiving the position information of the ground station 150.
In the meantime, the airship 100 should maintain reliable communication link to perform the functions mentioned above, and many techniques have been developed for it as below.
Firstly, according to S/W techniques, these methods lower the error rate of data by communication system using signal process and modulation to maintain reliable communication link between airship and ground station.
According to H/W techniques, many antennas are used. They include dual polarization antenna using vertical and horizontal polarization in the same time, high gain low lobe antenna and adaptive antenna.
However, conventional methods mentioned above have problems as below.
That is, the conventional methods need many test processes such as the test of database to reduce error rate that happens in communication link maintenance process. And consequently, cost gets higher for communication link maintenance.
According to one of conventional methods, an airship 100 is equipped with omni-directional antenna for communication link maintenance, but this method has low efficiency on electric power.
And, there is no method regarding to steering main beam direction and tilting polarization between an airship 100 and ground station 150 by using GPS 120 to maintain reliable communication link.
The present invention was devised to solve the problems mentioned above.
An object of the present invention is to provide a system for tilting polarization and steering main beam of airship antenna, which can maintain reliable communication link by aligning polarization between airship antenna and ground station antenna based on information of azimuth and elevation of airship using GPS.
Other object of the present invention is to provide a system for tilting polarization and steering main beam of airship antenna, which can maintain reliable communication link by aligning main beam between airship antenna and ground station antenna based on information of azimuth and elevation of airship using GPS.
Still another object of the present invention is to provide a system for tilting polarization and steering main beam of airship antenna, which can provide safe control for devices in airship by tilting polarization and steering main beam between airship antenna and ground station antenna to maintain reliable communication link.
In order to achieve the object, a system for tilting polarization and steering main beam of airship antenna according to the present invention comprises: a 1st GPS receiver, which is located in the airship; a 2nd GPS receiver, which is located in the ground station; an airship antenna database for extracting the radiation pattern information of airship antenna and polarization information according to the posture of the antenna based on the position information of the airship; a ground station antenna database for extracting the radiation pattern information of ground station antenna and polarization information according to the posture of the antenna based on the position information of the ground station; a polarization and main beam direction correction operating device for computing the correction value of polarization and main beam direction of the airship antenna and the ground station antenna based on the position information of the airship and the ground station received from the 1st GPS receiver and the 2nd GPS receiver; and an airship antenna controller for correcting the posture of the airship antenna by controlling the tilting polarization and the steering main beam direction of the airship antenna based on the corrected value received from the polarization and main beam direction correction operating device.